Wu Yaqi, Dorresteijn Joren M, Weckhuysen Bert M
Inorganic Chemistry and Catalysis group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
Hydrogen Energy Utilization and Energy Storage Technology Laboratory, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, P. R. China.
ACS Catal. 2024 May 29;14(11):9093-9103. doi: 10.1021/acscatal.4c01061. eCollection 2024 Jun 7.
Metallocene immobilization onto a solid support helps to overcome the drawbacks of homogeneous metallocene complexes in the catalytic olefin polymerization. In this study, valuable insights have been obtained into the effects of pore size, linker composition, and surface groups of metal-organic frameworks (MOFs) on their role as support materials for metallocene-based ethylene polymerization catalysis. Three distinct Zn-based metal-organic frameworks (MOFs), namely, MOF-5, IRMOF-3, and ZIF-8, with different linkers have been activated with methylaluminoxane (MAO) and zirconocene complexes, followed by materials characterization and testing for ethylene polymerization. Characterization has been performed by multiple analytical tools, including X-ray diffraction (XRD), scanning electron microscopy (SEM), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and CO Fourier transform infrared (FT-IR) spectroscopy. It was found that the interactions between MOFs, MAO, and the zirconocene complex not only lead to both catalyst activation and deactivation but also result in the creation of multiple active sites. By alteration of the MOF support, it is possible to obtain polyethylene with different properties. Notably, ultrahigh molecular weight polyethylene (UHMWPE, = 5.34 × 10) was obtained using IRMOF-3 as support. This study reveals the potential of MOF materials as tunable porous supports for metallocene catalysts active in ethylene polymerization.
茂金属负载于固体载体上有助于克服均相茂金属配合物在催化烯烃聚合反应中的缺点。在本研究中，对于金属有机框架材料（MOF）的孔径、连接体组成和表面基团对其作为基于茂金属的乙烯聚合催化载体材料的作用的影响，已获得了有价值的见解。三种具有不同连接体的独特锌基金属有机框架材料（MOF），即MOF-5、IRMOF-3和ZIF-8，已用甲基铝氧烷（MAO）和二茂锆配合物进行了活化，随后进行了材料表征及乙烯聚合测试。通过多种分析工具进行了表征，包括X射线衍射（XRD）、扫描电子显微镜（SEM）、凝胶渗透色谱（GPC）、差示扫描量热法（DSC）和CO傅里叶变换红外（FT-IR）光谱。结果发现，MOF、MAO和二茂锆配合物之间的相互作用不仅导致催化剂的活化和失活，还会产生多个活性位点。通过改变MOF载体，可以获得具有不同性能的聚乙烯。值得注意的是，使用IRMOF-3作为载体获得了超高分子量聚乙烯（UHMWPE， = 5.34 × 10）。本研究揭示了MOF材料作为用于乙烯聚合的茂金属催化剂的可调谐多孔载体的潜力。
